ECG Terminology

Ablation

The removal, isolation or destruction of cardiac tissue or conduction pathways involved in arrhythmias.

Algorithm

A set of precise rules or procedures programmed into a pacemaker or defibrillator that are designed to solve a specific problem.

Anti-arrhythmic Drugs

Medicine that corrects irregular heartbeats and slows down heart beats that beat too fast.

Anti-Tachycardia Pacing (ATP)

Short, rapid, carefully controlled sequences of pacing pulses delivered by an ICD and used to terminate a tachycardia in the atria or ventricles.

Arrest (Cardiac)

 Failure of the heart to pump blood through the body. If left untreated, it is dangerous and life-threatening.

Arrhythmia

 Any heart rhythm that falls outside the accepted norms.

Atrial fibrillation (AF)

 Very fast, disorganized heart rhythm that starts in the atria.

Atrial Flutter (AFL)

Fast, organized atrial rhythm.

Atrial Tachycardia (AT)

 A rapid heart rate that starts in the atria (includes AF, and AFL)

Atrioventricular (AV) Node

 A section of specialized neuromuscular cells that are part of the normal conduction pathway between the atria and the ventricles. (A junction that conducts electrical impulses from the atria to the ventricles of the heart.)

Atrioventricular (AV) Synchrony

 The normal activation sequence of the heart in which the atria contract and then, after a brief delay, the ventricles contract. AV Synchrony optimizes the heart’s output of blood and produces the greatest efficiency of the cardiovascular system.

Atrium

The heart is divided into four chambers. Each of the two upper chambers is called an atrium. (Atria is the plural form of atrium.) Either of the two upper chambers of the heart, above the ventricles that receive blood from the veins and communicate with the ventricles through the tricuspid (right) or mitral (left) valve.

Bradycardia (Bradyarrhythmia)

A heart rate that is abnormally slow; commonly defined as under 60 beats per minute or a rate that is too slow to physiologically support a person and their activities.

Cardiac Arrest

Failure of the heart to pump blood through the body. If left untreated, it is dangerous and life-threatening.

Cardioversion

The process of restoring the heart’s normal rhythm by applying a controlled electric shock to the exterior of the chest.

Chronic lead

 A pacemaker or ICD lead which has been implanted in the past.

Chronotropic incompetence

 The inability of the heart to increase its rate appropriately in response to increased activity or metabolic need,

Defibrillation

 The Process in which an electronic device sends and electric shock to stop an extremely rapid or irregular heartbeat and restore the normal heart rhythm.

Diagnostics

 Data gathered by an ICD or pacemaker to evaluate patient rhythm status, verify system operation, or assure appropriate delivery of therapy options.

Dual-Chamber Pacemaker

A pacemaker with two leads (one in the atrium and one in the ventricle) to allow pacing and/or sensing in both chambers of the heart to artificially restore the natural contraction sequence of the heart.

Ejection Fraction

A measure of the output of the heart with each heartbeat.

Electrocardiogram (ECG)

A printout from an electrocardiography machine used to measure and record the electrical activity of the heart.

Electromagnetic Interference (EMI)

 Equipment and appliances that use magnets and electricity have electromagnetic fields around them. If these fields are strong, they may interfere with the operation of the ICD.

Electrophysiology (EP) Study

The use of programmed stimulation protocols to assess the electrical activity of the heart to diagnose arrhythmias.

Fibrillation

A chaotic and unsynchronized quivering of the heart during which no effective pumping occurs. Fibrillation may occur in the atria or the ventricles.

Heart Block

 A condition in which electrical impulses are not conducted in the normal fashion from the atria to the ventricles. May be caused by damage or disease processes within the heart.

Hemodynamics

The forces involved in circulating blood through the cardiovascular system. The heart adapts its hemodynamic performance to the needs of the body, increasing its output of blood when muscles are working and decreasing output when the body is at rest.

Holter monitoring (Also called ambulatory monitoring.)

 A technique for the continuous recording of electrocardiographic (ECG) signals, usually over 24 hours, to detect and diagnose ECG changes.

ICD(Implantable Cardioverter Defibrillator)

is an implanted device used to treat abnormal, fast heart rhythms.

several types of therapies are used by the ICD including cardioversion, defibrillation, and anti-tachycardia pacing

Ischemia

 Insufficient blood flow to tissue due to blockage in the blood flow through the arteries.

Lead

 In an ICD system, the wire or catheter which conducts energy from the ICD to the heart, and from the heart to the ICD.

Left ventricular dysfunction

A heart condition in which the heart is unable maintain normal cardiac output due to a deficiency in the left ventricle.

Myocardial infarction

Death of a portion of the heart muscle tissue due to a blockage or interruption in the supply of blood to the heart muscle.

Myocardium

The middle and the thickest layer of the heart wall, composed of cardiac muscle.

Premature atrial contraction (PAC

 contraction in the atrium which is initiated by an ectopic focus and occurs earlier than the next expected normal sinus beat.

Premature ventricular contraction (PVC or VPD)

A contraction in the ventricle which is initiated by an ectopic focus and occurs earlier than the next expected normal sinus or escape rhythm beat.

Sinoatrial (SA) Node

 The heart’s natural pacemaker located in the right atrium. Electrical impulses originate here and travel through the heart, causing it to beat.

Sudden cardiac death (SCD)

Death due to cardiac causes within 1 hour of the onset of symptoms, with no warning.

Supraventricular tachycardia (SVT)

 A rapid heartbeat originating from above the ventricles.

Syncope

 Fainting, loss of consciousness, or dizziness which may be due to a change in cardiac rhythm (arrhythmia) or other causes.

Tachycardia (Tachyarrhythmia)

 Rapid beating of either or both chambers of the heart, usually defined as a rate over 100 beats per minute.

Ventricle

one of the two lower chambers of the heart

Ventricular Fibrillation (VF)

Very fast, chaotic, quivering heart contractions that start in the ventricles. During VF, the heart does not beat properly. This often results in fainting. If left untreated, it may result in cardiac arrest. Blood is not pumped from the heart to the rest of the body. Death will occur if defibrillation is not initiated within 6 minutes from the onset of VF.

Ventricular Tachycardia (VT)

A rapid heart rate that starts in the ventricles. During VT, the heart does not have time to fill with enough blood between heart beats to supply the entire body with sufficient blood. It may cause dizziness and light-headedness.

AA-Antiarrhythmic

is a medication used to prevent and treat abnormal heart rhythms.

AF-Atrial fibrillation

an rapid heart rate that commonly causes poor blood flow

ATP-Anti-tachycardia pacing

a pain-free method used by implantable cardioverter defibrillators(ICDs) to terminate ventricular tachycardia(VT)

AVID- Antiarrhythmics Versus Implantable Defibrillators study

is a large, randomized study that compared the effectiveness of two treatment strategies for patients who had survived life-threatening ventricular arrhythmias.

CABG-Coronary artery bypass graft

 a surgical procedure that restores blood flow to the heart by creating a new pathway around blocked arteries.

CAD-Coronary artery disease

damage or disease in the heart’s major blood vessels

CASH- Cardiac Arrest Study Hamburg

was a research study that compared different treatments for people who survived cardiac arrest caused by dangerous heart rhythms.

CHD-Coronary heart disease

a condition where the arteries supplying blood to the heart narrow or become blocked due to plaque build up

CHF-Congestive heart failure

the heart’s capacity to pump blood cannot keep up with the body’s need

DFT- Defibrillation threshold

the minimum amount of energy needed to reliably restore a normal heart rhythm after it has been disrupted by a life-threatening arrhythmia.

EF-Ejection fraction

is a percentage that measures how much blood the left ventricle pumps out with each heartbeat

EP-Electrophysiologic

the study of electrical properties of biological cells and tissues, with a focus on how electrical signals affect the function of living organisms.

EPS Electrophysiologic Study

a diagnostic test that examines the heart’s electrical system to identify and understand the causes of irregular heartbeats(arrhythmias)

Hypertrophic cardiomyopathy(HCM)

a heart condition where the heart muscle, particulary the left verntricle, becomes abnormally thick.

Implantable cardioverter defibrillator(ICD)

a small, battery-powered device placed under the skin to monitor and correct dangerous heart rhythms(arrhythmias)

 Length of stay(LOS)

the duration a patient spends in a healthcare facility, from admission to discharge

LQTS(Long Q-T syndrome)

a heart rhythm disorder that can cause fast,erratic heartbeats, potentially leading to fainting, seizures, or even sudden cardiac arrest